Building block



FIG. 1 is a perspective view of a building block showing my design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is another perspective view of a building block showing mydesign.

The broken lines are for the purpose of illustrating portions of thebuilding block that form no part of the claimed design.

CLAIM The ornamental design for a building block, as shown anddescribed.